To Love a Beast
by AlwayzHuman
Summary: Mabel makes a deal with Bill to save her brother. The catch: she must become his bride. Kind of a Beauty and the Beast story. HIATUS
1. Chapter 1

Chapter 1: Deal

The day started out ordinary enough. The weather was perfect and the sky was blue with the birds chirping happily and everything as it should be in Gravity Falls. Well… until the twenty year old Mystery Twins accidentally had to chase a certain evil Dorito into the woods.

"How is he even alive?" Mabel asked as she ran right next to her brother, making sure he didn't run into anything while he flipped through his Journal. "Didn't he become a statue?"

"I don't know how he is no longer a statue but we are definitely going to find out," the male twin answered. Unfortunately, the twins weren't expecting to have a second demon on their hands. This demon was leaning against one of the many trees that were around the area that Bill had led them to. At first glance, the new demon seemed to be just an ordinary human but if someone were to look at him closely, anyone could see his tar like hair, scaley skin, and dangerously violet eyes. He wore a black t-shirt and jeans with a pair of matching black boots to blend in with humans as much as possible.

"So glad you could make it, Mortem!" Bill cheered as he hovered over to the man.

"These are the pathetic humans you've been having troubles with?" Mortem asked in a flat tone and emotionless features. "They seem to be nothing but a bunch of kids."

"Be careful what you say," Bill amusedly warned. "They were able to defeat me at my most powerful time."

"That would be because you were counting your eggs before they hatched. An easy mistake for those with large egos such as yourself. A simple death spell should eliminate both of them," Mortem said as he conjured up two black energy balls. Bill's eye widened when he realized what Mortem was planning to do. The dream demon immediately sent a barrier towards the twins, who had just managed to catch up to the two demons, right as the other demon sent one of the energy balls towards Dipper. The lethal projectile hit the male twin in the chest just as the barrier went up. The second energy ball then hit the barrier right in front of Mabel, making her flinch back before she could race to her fallen brother. Dipper was barely breathing and Mabel became scared of losing him. Bill whirled on Mortem, turning red with anger. He may have been a demon but he does not agree to actually killing them. He'll turn them to stone, trap them in a bubble, trick them, lie to them, but never killing them.

"KILLING THEM WAS NOT PART OF THE PLAN!" Bill shouts at the other demon. "THEY COULD STILL BE USEFUL!"

"Relax, Cipher," the demon said with a shrug. "You needed help with those kids, I helped you by trying to kill those low life beings. If you can't handle how a real demon is supposed to act, maybe you should return to your original self." Bill merely growled at the demon with hatred, knowing if they got in a fight Mortem would easily win.

"Begone, Mortem," Bill growled out. With a snap of his fingers, Mortem was gone.

"Dipper! Wake up!" Mabel cried, getting the triangular demon's attention. Bill took down the shield and hovered over to Mabel and the unconscious Dipper. The dream demon could see Dipper slowly and painfully dying in his twin's arms. Bill didn't want this. Sure he wanted world domination, but he didn't want anyone actually dying because of him.

'If I use the Life-For-A-Life spell, then Pine Tree would be fine. But that requires someone to sacrifice their life by dying, slavery, or marriage to the demon they make the deal with,' Bill thought to himself. Then he remembered his mother's warning from a week ago that he needed to satisfy. He still had four months to complete his mother's request but what could getting it done early hurt? 'Shooting Star would be more than willing to give her life for her brother.' Bill began formulating his speech in his head so that he could trick Mabel to make a deal with him and have her in his clutches while appeasing his relentless mother. Of course he was interrupted by the girl that was crying on the ground.

"Can't you save him?" The girl cried out in panic.

"I would, Shooting Star, but that would require me making a deal to use the Life-For-A-Life sp-" Bill was once again interrupted by the female twin.

"DEAL!" Mabel shouts, shoving her hand towards Bill. The demon was slightly surprised that she agreed without him having to really say anything but took her hand and finalized the deal before she could change her mind. The dream demon snapped his fingers while saying some sort of incantation and in a matter of seconds, Dipper's body was covered with blue flames. When the flames were gone, Mabel could see her brother breath more easily and he seemed to just be sleeping. She hugged her brother while telling him many apologies. Bill, witnessing this, rolled his eye at the show before him.

"Yeah, yeah!" Bill interrupted, making Mabel glare at him. "Lovey-dovey, mushy fluffiness and all that stuff. Are you ready to go yet?" Mabel hugged her brother one last time, saying her goodbye, before she stood up and took a breath while walking to the evil nacho.

"I'm ready to die now," Mabel said in a sad voice. Bill began laughing at the brunette before him, making her glare again but this time with a mixture of confusion.

"You're not going to die, Shooting Star," Bill said. Mabel gave him a confused look. "Sure that is one of the ways to complete the contract but that isn't what I want. When you shook my hand, you agreed to become my bride," Bill said with a smirk in his voice. Mabel gave him a weird look as images of married couples ran through her head. She didn't want any of it with Bill. One question made it's way to Mabel's mouth.

"How is that even going to work out? I mean, you're a triangle."Bill chuckled at her before summoning his cane. He used the hooked end to wrap around Mabel's waist and pulled her closer while blue flames engulfed his body. Once Mabel was close enough to be licked by the flames, the fire disappeared and a man about her age with blond hair and a suit stood before her. She immediately thought he was super cute and was about to flirt while she began to blush…

Until she realised he was holding Bill's cane…

Because he is Bill…

And they were very close at the moment, making her blushed even more.

"What do you think, Shooting Star?" Bill asked, knowing he was having an effect on her, and stroked down her cheek and to her jaw where he snapped it closed. By doing this, Bill snapped his victim out of her trance. Mabel had no way of hiding her cherry red face from the demon.

"I think you're crazy!" Mabel said, slowly getting angry. "Besides, I'll die long before you ever will."

"It won't work that way, Shooting Star," Bill said with a smirk. "On the day of our wedding, our souls will become one and you will share my life span." Mabel's face paled. She would have to live many years without her family. Bill snapped his fingers and they appeared in a mansion. They stood in the entry way. To her right, Mabel could see a dining room that had two door ways, one leading to the kitchen and the other leading to a ballroom. To her left seemed to be a living room that was connected to a garden. In front of them was a large staircase that had doors of many colors. Bill stayed close to her, listening for something but there was no sound.

"Wow!" Mabel said in amazement. Bill quickly covered her mouth, making her confused. Bill continued to listen for a moment longer before he took his hand off of Mabel's mouth.

"Keep quiet," Bill whispered with urgency. Mabel nodded, still confused by his actions, before she allowed him to lead her up the stairs and down several halls before going up some more stairs. They were just about to pass by a burgundy, plaid door when said door started to open. Bill quickly shoved Mabel behind him, making her stuck between the wall and the demon. She was easily hidden from view as an old woman with silvery hair walked out in her plaid pajamas.

"Hello, little one," the old woman said in a raspy voice.

"Hello, grandmother," Bill said politely, surprising Mabel. "What are you doing up from your nap?"

"I heard two pairs of footsteps," the old woman said. "I guess I misheard. Farewell, little one."

"Sleep well, grandmother," Bill said politely as Mabel stayed in shock. Once the old woman closed her door, Bill started pulling Mabel again. They got to a bright yellow door without any more incidents and went through before Bill immediately closed the door again, making everything pitch black. The dark scared Mabel, thanks to a certain demon, and she began to panic.

"B-bill?" Mabel stuttered in the dark.

"I'm over here, Shooting Star," Bill said from somewhere to her left. He hadn't moved away from the door so he could stop Mabel from trying to escape, if she even had that thought. When he heard her call his name, he could hear the fear in her voice and knew it was because of him. He heard her shuffle toward him a few steps before she gasped from surprise and crashed into Bill, who place one arm around her waist and the other around her shoulder while she rested her hands on her chest.

She had tripped.

Bill had caught her.

Mabel was still shaking and Bill smirked, knowing he was the cause of her fear. However, his smirk died on his lips as he felt Mabel's breath move up his chest, passed his neck, and up to his lips. It was then that he realized that she was so close to him. What was worse, in his eye, was the fact that he didn't mind. In fact, he liked how close she was to him. He pulled her closer very slowly, as if he was trying not to frighten her. Her shaking, without Mabel realizing it, stopped altogether. An emotion, one that Bill didn't recognize, began to make it's presence known to the blond demon. The emotion made his heart beat fast as if he was running a race. It made him want to hold the human girl closer. It made him feel like a magnet was pulling him to her. To her lips. He was centimeters away from her lips. She never pushed him away. He was about to close the distance between their lips.


	2. Chapter 2

**I don't know if I've said this or not but this story is not related to my other one, "From the Future". However, I am reusing the Back story for Bill form the other one. I had this typed out earlier but my computer ate it and it took me a bit to find it. My thanks to the five people who reviewed! Updates will be slow for a bit because Finals are here but I get out of school in two day (WOOHOO!) so the updates should be coming if I can get myself out of bed for it. I am also going to take a while because I need to make a one-shot with Pyronica in it as a request from someone else. Hopefully I will write it well enough. ANYWAYS! I'm getting side tracked.**

 **There is some Mabill fluff in this chapter. And remember that almost kiss Mabel and Bill almost had? That's where it starts. Enjoy!**

Chapter Two: The Yellow Room

It made him want to hold the human girl closer. It made him feel like a magnet was pulling him to her. To her lips. He was centimeters away from her lips. She never pushed him away. He was about to close the distance between their lips.

Then the lights suddenly turn on, blinding the two by the door. Bill quickly flipped them, pinning the brunet to the door just as a fire ball hit his back, making him grunt in pain. Mabel squeaked a little at the sudden attack and started shaking again.

"Are you okay?" Mabel asked, unsure if he was actually hurt or if he just grunted from surprise. Bill absentmindedly started to rub her arm, comforting and reassuring her, as he turned his head to look at the attacker. There stood a girl dressed in a red and black jumper with matching knee boots and long, flowing, silver hair.

"Not now, Xael," Bill growled out.

"What's wrong?" The woman, Xael, asked. "Did those silly human kids beat you again?" Xael mocked. Bill moved out of the way just enough to show off Mabel. Xael's eyes flicked to Mabel and her mouth changed from a smirk to an 'o' form. "She's pretty," Xael said after she recovered from her shock. "When you said you already had a girlfriend, I thought you were just lying to buy yourself more time." She walked closer to get a better look at the girl but stopped when Bill pulled the brunet away. "Calm yourself, big brother. I will not be the one to harm her." Bill seemed to relax a bit before tensing at her next words. "Enfado, however, might." Bill's eyes changed from shock to questioning to anger in seconds.

"Over my dead body," Bill said in the most serious voice Mabel had ever heard from the demon. "Why do you even bring him up? He doesn't stay here anymore," Bill asked, growing more mad by the second.

"Well…" Xael said a little nervously. Bill turned completely red, even his hair and eyes were red. "He might or might not have changed his mind and started living here again." Bill started to turn white with anger as Xael snuck over to Mabel to pull her away from her brother before sneaking out of her brother's room.

"WHY THAT LITTLE-!" Bill was interrupted by Mabel's voice.

"Bill?" Mabel asked, she was still pinned to the door.

"WHAT?!" Bill shouts, making Mabel flinch. Bill forced himself to calm down, already guessing she had some questions, and led her to the yellow bed in the middle of the room while he slowly returned to his original color. To the left of Mabel was a balcony, to her right were two closets with a mirror in between the two, and behind the bed was the bathroom. The dream demon laid on his stomach while Mabel sat next to him on the bed. Mabel could now see the burns from the attack. "Ask away, Shooting Star," Bill said, startling her from her staring contest with his back.

"Huh?" Mabel asked, confused. She could also slightly hear something in his voice. Sleepiness, perhaps?

"I know you have some questions. Now spill." Mabel thought for a minute. She got up and went to the bathroom to gather some things. When she came back, Bill saw Mabel holding a rag, a bowl of water, and peroxide. "Don't worry about that, kid. I'll just go out later and heal myself. Mabel shook her head.

"I need to do something while I ask questions," Mabel said as she sat herself next to him once again. She dipped the fabric into the water and began to dab at the burnt flesh. Bill hissed in pain as she continued to disinfect it.

"This is not the funny kind of pain," Bill mumbled. "You know, if you wanted to take a little revenge out on me by using those, you could have just told me," Bill said a little louder, making Mabel roll her eyes.

"This would be easier if your shirt wasn't still on," Mabel grumbled, making Bill chuckle.

"Again," Bill answered, "you could have just said so." Bill sat up a bit and took his jacket and fancy shirt off. Mabel turned her head away as she fought, and sorely losing, to hide her blush. The dream demon laid on his stomach again so Mabel could dab at his back with the water soaked cloth. The brunet did her best to pretend that she was merely cleaning one of Dipper's wounds but the blond hair she saw in the corner of her eye always threw her off. So she tried distracting herself with questions. I mean, Bill did offer to answer them anyways.

"First question: Why do you have to leave to heal yourself? Couldn't you just use your powers?"

"In short, if I am in the mansion then my powers are blocked which means I can't even heal myself," Bill said, hissing again when Mabel dabbed at one of the spots near his spin.

"But that girl was able to use her powers. Why is she able to use her powers?"

"Xael? She's is my little sister. She isn't a demon so she can still use her powers. I'm the only demon in this mansion," Bill said, a sad undertone in his voice.

"If she isn't a demon, then what is she? And why are you the only demon here? And who is Enfado? And what is this place?" Bill flinched when she mentioned Enfado, but that could have just been him flinching at a sore spot.

"Slow down, Shooting Star," Bill said with a weak chuckle. "One question at a time. Xael is a goddess. She is, in short, a spark. She is the spark of life that occurs in a mother's womb, the spark that occurs when people first experiences something new, and she is also the one that snuffs it all out when it is time for death. Xael is just one in a set of octuplets. Her sisters are Anouk, Elspeth, and Lilou. Her brothers are Azarias, Finbar, Loch, and Zoran. They're all pretty cool and nice but they aren't to me anymore. They all hate what I've become, except Xael. She is the only one who was there."

"Where?" Mabel asked, now curious. If he wasn't always a demon, what happened?

"Relax, Shooting Star. I'll get there, just be patient," Bill cooed. "That question, along with why I'm the only demon and who Enfado is, all correspond with each other. As for what this place is, it's called the Cipher Mansion. It's where my whole family lives." Mabel nodded in understanding as she switched from the water to the peroxide.

"This is going to sting a bit," Mabel warned. Bill hummed a reply before she proceeded to pour some onto his back. Bill hissed again before diverting his mind to a story.

"A really long time ago, when Xael was younger, littler, there were no demons. Just Gods and Goddesses. Then, one day, a god, I can't remember who, decided they would rather rule over the humans rather than let them have their own free will. Some other beings agreed with him and soon war broke out. The Cipher Mansion was a haven for many. Enfado being one of them. There was a young god living in the mansion, he was still learning his powers. He loved disorder but he would never have gone so far as to hurt or put someone in danger. He was good. A little disorderly but still good. He and one of his little sisters ended up befriending Enfado and the three of them were practically inseparable." Bill's eyes became distant. Mabel was about to question it but he continued to talk before she got the chance. "The war didn't last long and those who wanted to enslave the humans were cast aside as demons. One day, the young god and his little sister caught Enfado trying to communicate with one of the traitor Gods. Enfado and the young god fought, the little sister had been thrown against a wall by Enfado and was too weak to fight. The little sister watched as the boys battled. The young god took the device Enfado was using to contact the demons and knocked him to the ground. At that same moment, the parents of the young god came in. Enfado took that chance to frame the young god. Even when the little sister tried to defend her brother, Enfado simply said that she hit her head and probably wasn't thinking straight. The parents of the young god set their eldest son as a demon. Even after a decade passed, the rest of the young no-longer-a-god's family, with the exception of his little sister and his grandmother, never trusted him and even framed him for things he didn't do. Like steal the cookies from a cookie jar." Mabel could see the sadness and anger in his voice and eyes. She could tell, before he continued, that he was talking about himself. _He_ was the young god and _Xael_ was the little sister. "Eventually, I just got tired of being accused of being evil and decided: 'Hey! If they think I'm evil, then they wouldn't mind if I was evil for real.' So I left and went to the dreamscape. Made new friends, this time they were all demons; changed my form, my beloved triangle form; started plotting the weirdmageddon, this was around the same time I met Sixer; and then I lost everything again, mainly because of you and Pine Tree. I was able to escape my stone prison because of my mother. She was tired of the way I've been living and wants me to marry. Of course she decided to tell me this in front of my whole family. I don't want to marry so I told my mom I already had a girlfriend, even though I didn't. I was hoping to buy myself more time but my mom seemed to see right through me and told me I had four months to get hitched or she is going to block all of my powers and make me live in the human world until I died. I figured that four months would give me more than enough time to find some silly human to push to the side after I'm hitched. Once I left her presence, I found Mortem and made a deal with him to try to punish you and your brother for defeating me last time but he went too far and… well… you know the rest." Mabel finished cleaning his wound and was back in the bathroom looking for bandages.

"Why didn't you tell Ford or Dipper? Or even me when we first met?" Mabel asked. Bill shrugged from where he was on the bed.

"I didn't know you guys all that well and, to be honest, I was mad at my family," Bill explained. "I would have done anything at the time for them to listen. When they kept pushing me away, I rebelled against them. Compared to human years, I would have been considered a teenager at the time." Mabel sat back down next to him. "You don't need to do that. I'm still a demon who can heal himself. I just can't be in the mansion to do so," Bill said, seeing the bandages. Mabel looked from the bandages to Bill's back, embarrassed that she had forgotten.

"Right..." Mabel mumbled, making Bill chuckle. "Do your parents still not believe you? About what happened with Enfado, I mean." Bill shook his head as Mabel laid on her stomach, her arm lightly touching his and making his own stomach flutter. He ignored it, however. "How about your grandmother? Does she believe you?" Bill nodded his head.

"She practically raised me. Out of everyone I know, and I know a lot of beings, my grandmother was the one who knew me best," Bill explained. "You might have seen her. She was the one to open the door in the hall on the way here."

"Really? She seemed so cute!" Mabel squealed, making Bill smile a little bit.

"She may seem that way now but wait until she decides to correct your manners or when she gets really mad. That woman is the only one that terrifies me other than Stan," Bill said before shivering, making Mabel laugh. Bill became serious again but still kept the smile on his face. "Now that I think about it, I trust your family a lot. About as much as my sister and grandmother." Mabel raised an eyebrow at him. "What I'm trying to say here is that I'm glad I chose you for a bride."

"I thought you were only marrying because your mom told you to," Mabel said, a hint of playfulness in her voice. Bill rolled his eyes.

"It might still be too early to tell, but I think I might enjoy being bound to you," Bill said before getting to his feet. Mabel flipped to her back so she could follow the shirtless Bill with her eyes. "It's getting late and you need sleep. I'm going to go out to heal," Bill said as he went to the closet closest to the door to put on a new shirt. "Then I'm coming back. Stay in the room, don't leave the room until I come back. I'll walk you to the table every meal time so you won't have to worry about getting lost." Mabel nodded and Bill left. The brunet curled up in to a ball on the bed, thinking about her own family. How she didn't get a proper chance to say goodbye, how she just left Dipper unconscious in the woods, how she will never see them again. She began to cry silent tears. She'll keep up a cheerful face in front of Bill. Since he told her so much about himself within the first day of making the deal and all that he went through, he needed a real friend. So she vowed that night to stay cheerful for his sake. Mabel fell asleep with tears in her eyes, for missing her family and friends, and a smile on her face, for she had made a new friend.

 **Hehe! No kissing yet, sillies! It's waaaaaay to early for that. They need to get to no each other better first. I hope you all enjoyed! Please leave a review and let me know what you think.**


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